Compositions containing substituted benzotriazoles



United States Patent 3,413,227 COMPOSITIONS CONTAINING SUBSTITUTED BENZOTRIAZOLES Donald Kearey Howard, Levenshulme, and Donald Richard Randell, Stockport, England, assignors to Geigy Chemical Corporation, Ardsley, N.Y., a corporation of New York No Drawing. Continuation-impart of application Ser. No. 416,603, Dec. 7, 1964. This application Mar. 17, 1967, Ser. No. 623,826

Claims priority, application Great Britain, Dec. 6, 1963,

48,223/ 63; Jan. 24, 1964, 3,084/ 64 Claims. (Cl. 252-515) ABSTRACT OF THE DISCLOSURE Benzotriazoles substituted in the 5-position by C alkyl or C alkanoylamino are useful as 1) corrosionor tarnish-inhibitors in metal polishes and (2) agents to act as metal deactivators and to inhibit the degradation of function in functional compositions such as lubricants and polypropylene coatings.

This application is a continuation-in-part of our patent application Ser. No. 416,603, filed Dec. 7, 1964, now abandoned.

The present invention relates to compositions for application to metal surfaces containing new substituted benzotriazoles as corrosion or tarnish inhibitors and to functional materials in contact with a metal and containing, as metal deactivators, the said novel benzotriazole derivatives.

The ability of benzotriazole to perform as an antitarnish agent in various media is well-known. Thus this compound has been recommended for use in such systems as detergents and antifreeze formulations.

We have now found, however, that certain S-alkyland S-alkanoylamino-benzotriazoles have antitarnish properties which are greatly superior to those of benzotriazole itself. This would not be expected since the introduction of any substituent into the benzotriazo-le system lowers the proportion of the active centre per molecule and consequently proportional reduction of the antitarnish effect per molecule of derivative would be anticipated.

Contrary to such expectation, however, we have found that there is a sudden and very marked increase in the anti-tarnish properties when the chain length of the alkyl substituent is increased from 1 to 2 carbon atoms, and that this increase is maintained and even further increased as the chain length is increased up to 20 carbon atoms.

Accordingly, the present application provides a composition for application to metal surfaces and particularly to a copper or copper alloy surface, containing, as corrosion or tarnish inhibitor, a minor proportion of a substituted benzotriazole of the formula:

wherein R is a straightor branched-chain alkyl group containing from two to twenty carbon atoms, or an alkanoylamine group containing from three to twenty carbon atoms.

If the substituent group R is alkyl, it may be, for example, ethyl, n-propyl, iso-propyl, n-butyl, isobutyl, tertiary-butyl, n-octyl tertiary-octyl, n-decyl, n-dodecyl, n-octadecyl or eicosyl. If the substituent group R is alkanoyl-amino, it may be, for instance, propionylamino,

butyoylamino, hexanoylamino, octanoylamino, decanoylamino, dodecanoylamino, or higher analogue containing up to twenty carbon atoms.

Preferred as corrosion or tarnish inhibitors among the compounds falling under Formula I are those in which R represents alkyl of from 4 to 12 carbon atoms, since these derivatives exhibit optimal tarnish-inhibiting properties in respect of treated magnesium and copper surfaces.

The production of the corrosion or tarnish inhibitors of Formula I is fully described and illustrated in our co-pending patent application Ser. No. 662,236, filed July 10, 1967.

The compositions of the instant application are preferably applied to the metal surface to be treated in the form of a solution or dispersion of the substituted benzotriazole in an inert solvent. The amount of benzotriazole in the composition should be sufficient to impart a tarnishinhibiting effect to the metal surface. The solvent employed in the composition of this application is naturally one which is entirely inert to the treated metal and to the substituted benzotriazole tarnish inhibitor. Suitable solvents are water, a lower alkanol such as methanol or ethanol, mineral oils or greases, ethylene glycol or other alkylene glycol and polyethylene glycol or other polyalkylene glycol such glycol solvents being commonly used as antifreeze bases, or mixtures thereof.

The compositions of this invention may be applied in any manner conventional for the treatment of metal surfaces. For example, the composition may be sprayed or padded on to the metal to be treated, or the metal to be treated may be immersed in the corrosion-inhibiting composition of the invention. After treatment, the composition of this invention may be removed from contact with the metal by, for instance in the case of water-soluble compositions, rinsing in water and drying off. Alternatively, the treated metal surface may be maintained in contact with the corrosion-inhibiting composition, for instance in those cases in which the metal surface is packed in grease or coated with oil.

If the metal surface is treated with the composition of the invention in the form of a solution which is then removed from contact with the metal, such a solution preferably contains a proportion of the benzotriazole of Formula I within the range of from 0.01% to 5%, more preferably within the range of from 0.1% to 1.0% by weight.

On the other hand, if the composition of the invention is maintained in contact with the treated metal surface after application, lower proportions of the substituted benzotriazole composition may be employed, for example from 0.001% to 5%, more preferably from 0.01% to 1% by weight.

The present invention also provides, as a second aspect, a functional material susceptible to deterioration .of function in contact with a metal, particularly copper or a copper alloy, to which has been added, as metal deactivator, a minor proportion of a substituted benzotriazole having the Formula I as hereinbefore defined.

Typical functional materials which are included within the scope of this invention include, for instance, synthetic polymeric material such as polyethylene, polypropylene, natural and synthetic rubbers, mineral oils, antifreeze compositions and synthetic ester lubricants. Particular embodiments of this aspect of the present invention concern polypropylene containing a compound of Formula I as a metal deactivator and synthetic ester lubricants containing a compound of Formula I as a metal deactivator.

Thus polypropylene has found wide application as a covering material for copper wire and other copper articles. Such wire or articles however can lead to rapid degradation of the surrounding polypropylene material unless this material contains a copper deactivator. The polypropylene composition of this invention has been found to exhibit a most surprising resistance to degradation compared with previously known compositions.

Synthetic lubricants, particularly those based on carboxylic esters, are the subject of another important embodiment of this invention. Such lubricants generally contain an antioxidant additive, for example dioctyl dipheuylarnine, which tends to bring about corrosion of any metal, particularly copper or copper alloy, in contact with the antioxidant. Consequently, in order to prevent such corrosion, synthetic lubricant compositions normally contain one or more metal, particularly copper, deactivators. Again, it has now been found that the synthetic lubricant functional compositions of this invention are much more stable to degradation set up by copper corrosion than conventional synthetic lubricant compositions containing, for instance, benzotriazole as the copper deactivator.

The proportion of the benzotriazole of Formula I which is present in the functional compositions of this invention should be sufficient to inhibit functional deterioration and may conveniently be from 0.01% to 5%, preferably from 0.05% to 2.0% by weight based on the total weight of the functional composition.

While the compositions of this invention may be used to treat, and the functional materials of this invention may come into contact with a wide variety of metals or alloys, for example iron or steel, silver, cadmium or alloys of these metals, the compositions and functional materials are particularly effective in the treatment or when in contact wth copper or copper alloys. For instance, the compositions are particularly effective in preventing tarnishing or corrosion of a copper surface due to attack by an atmosphere of hydrogen sulphide, ammonia or other noxious environment detrimental to the utility or appearance of the surface. Furthermore, the treatment of copper or copper alloy surfaces with the compositions of this invention may have the effect of enabling steam or other vapours to condense thereon as droplets, and the compositions are thus valuable in improving the heat transfer properties of copper or copper alloy condensers or other articles.

The present invention also provides a method of treating a metal surface, particularly a copper or copper alloy surface, in order to inhibit corrosion or tarnishing thereof, comprising contacting the metal surface with a composi tion containing, as corrosion or tarnish inhibitor, a minor proportion of a substituted benzotriazole of Formula I as defined hereinbefore.

The present invention still further provides, as a fourth aspect, a method of inhibiting the degradation of function of a functional material susceptible to degradation of function in the presence of metals, particularly copper or copper alloys, comprising incorporating into the functional material, a minor proportion, as metal deactivator, of a benzotriazole compound of Formula I as hereinbefore defined.

The following nonlimitative examples illustrate the present invention. Parts by weight shown therein bear the same relation to parts by volume as do kilograms to liters. Percentages are expressed by weight unless otherwise stated.

EXAMPLE 1.5-BUTY'LBENZOTRIAZOLE (A) 4-butyl-2-nitroacetanilide 511 parts by weight of p-butylaniline were mixed with 2,500 parts by volume of 'water and 2,044 parts by weight 4 anhydride and 79 parts by Weight of nitric acid at 35 C. The product was 4-butyl-2-nitroacetanilide, which was crystallised from petroleum ether (boiling point range 60 to 80 C.) to give a 92% yield as needle-shaped crystals having a melting point 76 C.

(B) 4-butyl-2-nitroanilide 200 parts by weight of 4-butyl-2-nitroacetanilide in ethanol (1,000 parts) produced as described in Example 1A were treated for 1 hour at reflux with 200 parts by weight of 40% aqueous potassium hydroxide solution.

The product was 4-butyl-2-nitroaniline having a boiling point 138 to 146 C. at 0.6 millimetre of mercury pressure. The yield was 78.5% of the theoretical yield.

(C) 4-butyl-1 :Z- henylenediamine 150 parts by weight of 4-butyl-2-nitroaniline, produced as described in Example 1B, were mixed with 600 parts by volume of ethanol and the mixture was hydrogenated in an autoclave at 100 C. and at an initial pressure of 50 atmospheres for 3 hours, in the presence of 1 part by Weight of Raney nickel.

The 4-butyl-1:2-phenylenediamine produced, the yield being 49.5% theoretical, was converted to the substituted benzotriazole as described in Example 1D without further purification.

(D) S-butylbenzotriazole 49 parts by weight of 4-butyl-l:2-phenylenediamine, produced as described in Example 1C, were suspended in 36 parts by weight of acetic acid. The mixture was admixed With a solution of 22.5 parts by weight of sodium nitrite in parts by weight of Water while stirring.

The product was S-butylbenzotriazole, obtained in 64.9% theoretical yield on purification from petroleum ether (boiling point range 60 to 80 C.) having boiling point 202 C. at 1 millimetre of mercury pressure, melting point 65 C.

EXAMPLE 2.5-DODECYLBENZOTRIAZOLE (A) 4-dodecyl-2-nitroacentanilide (B) 4-dodecyl-2-nitroaniline 4-dodecyl-2-nitroacetanilide, produced as described in Example 2A, was hydrolyzed by the procedure described in Example 113, the product being 4-dodecyl-2-nitroaniline in 86.2% yield.

The product had melting point 76 C. on purification from methanol.

(C) 4-dodecyl-l :2-phenylenediamine 80 parts by weight of 4-dodecyl-2-nitroaniline, produced as described in Example 2B, were mixed with 400 parts by volume of ethanol and the mixture was hydrogenated in an autoclave at C. and at pressure of 50 atmospheres for 3 hours by the procedure described in Example 1C.

The 4-dodecyl-l:2-phenylenediamine produced was crystallised from petroleum ether (boiling point range 40 to 60 C.) and had melting point 70 C. The yield was 80.5% theoretical.

(D) 5-dodecylbenzotriazole 55.2 parts by weight of 4-dodecyl-1:Z-phenylene-diamine, produced as described in Example 2C, were suspended in 24 parts by weight of acetic acid. The mixture was admixed with a solution of parts by weight of sodium nitrile in 24 parts by weight of water while stirring.

The product was 5-dodecylbenzotriazole, obtained in the form of white needle-shaped crystals on crystallisation from petroleum ether (boiling point range 60 to 80 C.) having melting point 76 C. The yield was 81.9% theoretical.

By carrying out the procedure described in Example 2, but using p-myristylaniline, p-palmitylanilide or p-eicosylaniline instead of the p-butylaniline starting material, the corresponding 5-myristyl-benzotriazole, 5-palmitylbenzotriazole or p-eicosylbenzctriazole is obtained. The p-alkylaniline starting materials may be made by the conventional method of reacting aniline with the corresponding alkanol, for instance in the presence of zinc chloride as catalyst.

EXAMPLE 3 .5 -ET HY LBENZOTRIAZOLE (A) 4-ethyl-2-nitroacetanilide 242.4 parts by weight of p-ethylaniline were mixed with 250 parts 'by volume of benzene, and 224.6 parts by weight of acetic anhydride were added drop-wise at 55 to 60 C. over 1% hours. The resulting mixture was then maintained at 60 C. for 1 hour and then was cooled at 0 C. to precipitate 4-ethylacetanilide. The product, obtained in 72.3% yield, was washed and found to have melting point 91 C.

163.3 parts by weight of 4-ethy1acetanilide were added to 450.2 parts by weight of 70% aqueous nitric acid and 765.8 parts by weight of acetic anhydride at to 40 C. for over 1 hour. The mixture was maintained at 40 C. for 3 hours more and then poured into water. A substantially quantitative yield of 4-ethyl-2-nitroacetanilide, having melting point 46 C. Was thus obtained.

(B) 4-ethyl-2-nitroaniline 208.3 parts by weight of 4-ethyl-2-nitroacetanilide, produced as described in Example 3A, Were refluxed for 30 minutes with 160 arts by weight of sodium hydroxide dissolved in 240 parts by volume of water and 1,000 parts by volume of ethanol. The resulting mixture was cooled and poured into iced water, thus yielding 4-ethyl- 2-nitroaniline, having melting point 47 C. in 72.6% yield.

(C) 4-ethyl-1 :Z-phenylenediamine 120 parts by weight of 4-ethyl-2-nitroaniline, in admixture with 400 parts by volume of ethanol, were hydrogenated in an autoclave at 100 C. and at an initial pressure of 50 atmospheres, in the presence of 1 part by weight of Raney nickel, until hydrogen uptake was comlete. P The catalyst was then filtered off, ethanol was distilled off, and the dark brown solid residue was recrystallised from a mixture of equal parts of petroleum ether (boiling range 60 to 80 C.) and benzene to produce 4-ethyl- 1:2-phenylenediamine having melting point C. in 99.7% yield.

(D) S-ethylbenzotriazole 40.9 parts by weight of the product of Example 3C were suspended in a mixture of 36 parts by weight of glacial acetic acid and 88 parts by volume of water. To this suspension was added, while stirring, 21.9 parts by weight of sodium nitrite in 37.6 parts by volume of water. The temperature was allowed to rise to 80 C. and the product was poured into water, extracted with toluene, washed out from the toluene extract with aqueous sodium hydroxide solution, and reprecipitated by treating the alkaline solution with hydrochloric acid.

The resulting brown oil solidified to give S-ethyl-benzotriazole having melting point 62 to 63 C. in a yield of 42.1%. On recrystallising from petroleum ether/benzene the product had melting point 66 C.

EXAMPLE 4 A specimen from the same bright acid-dipped copper foil was immersed in one of the following: 0.1% weight/ volume aqueous solution of benzotriazole; 0.1% weight/ volume aqueous solution of S-methylbenzotriazole; 0.1% weight/volume aqueous solution of 4-nitrobenzotriazole; 0.1% weight/volume aqueous solution of S-nitrobenzotriazole; 0.1% weight/ volume aqueous solution of benzotriazole-S-sulphonic acid; 0.1% weight/volume aqueous solution of benzotriazole-S-sodium sulphonate; 0.1% Weight/volume aqueous solution of S-butylbenzotriazole (as produced by the procedure described in Example 1); 0.1% weight/ volume aqueous solution of 5-dodecylbenzotriazole (as produced by the procedure described in Example 2); and 0.1% weight/volume aqueous solution of S-ethylbenzotriazole (as produced by the procedure described in Example 3). The nine immersed specimens were maintained at 65 C. for 5 minutes and they were then washed in distilled water and dried in hot air.

The resistance to tarnishing of the copper specimens was compared with that of a tenth specimen of the same acid-dipped, but otherwise untreated copper foil as a control, by exposing the specimens to an atmosphere containing 10 parts per million by weight of hydrogen sulphide. The time taken for the onset of visible tarnish was recorded as a measure of tarnish resistance.

The results were as follows:

Table 1 Specimen: Time in minutes Control 1 Treated with benzotriazole 5 Treated with S-methylbenzotriazole 5 Treated with 4-nitrobenzotriazole 5 Treated with S-nitrobenzotriazole 5 Treated with benzotriazole-4-sulphonic acid 7 Treated with benzotriazole-4-sulphonic acid sodium salt 5 Treated with 5-ethy1benzotriazole l5 Treated with 5-butylbenzotriazole 20 Treated with 5-dodecylbenzotriazole 20 In order to give a tarnish time of 20 minutes, as measured by the procedure described above, using benzotriazole as antitarnishing agent, it was necessary to use a 2% by weight solution of benzotriazole.

These results demonstrate that the compounds of the invention protect copper against tarnishing and that the protective properties are superior to that afforded by benzotriazole, S-methylbenzotriazole and other substituted benzotriazoles outside the scope of the present invention.

EXAMPLE 5 The following example illustrates the effectiveness of compounds of the present invention as additives to polypropylene to enhance the thermal stability of the polypropylene in the presence of copper.

Samples of a medium flow general stabilised polypropylene were each milled at 186 C. for 8 minutes, the additive under test being added to the sample after milling for 3 minutes, the milling being thereafter continued for a further period of 5 minutes. Each of the milled samples was cut into pieces of suitable size after removal from the mill and was compression moulded, allowing 2 minutes preheat time and then 5 minutes pressing under 20 to 30 tons force at 185 C., followed by cooling with circulating water. Each of the moulded sheets was cut into strips 3.25 inches long, 0.3 inch wide and 0.015 inch thick.

A series of specimens from each sheet were then placed heated in contact with copper turnings in an air oven maintained at C. The specimens were tested by removing them two at a time from the oven at intervals of 24 hours, allowing them to cool for 10 minutes and manually flexing the bottom of the specimens 0.25 inch through an angle of 360 degrees. The time by which the polypropylene sample became brittle was noted, thus giving a measure of the inhibition of each of the additives of the degradation action of the copper on the polypropylene tested. These times are given in the following table, where comparison is given with a similar polypropylene sample not milled with an additive.

Table 2 Time to becoming Additive in sample: brittle, days Control (no additive) 4 Benzotriazole 2 S-butylbenzotriazole 6 5-dodecylbenzotriazole 6 The S-butylbenzotriazole and the 5-dodecylbenzotriazole were produced by the procedures described in Examples 1 and 2 respectively,

EXAMPLE 6 (A) 78.5 parts by weight of S-nitrobenzotriaz-ole, dissolved in 500 parts by volume of dioxan, were hydrogenated with molecular hydrogen at 100 C. in the presence of Raney nickel as catalyst. The initial pressure was 50 atmospheres and the reaction was continued until the uptake of hydrogen was complete. Thet total reaction time was 3 hours.

The hydrogenated solution was filtered to remove the catalyst and the filtrate was then saturated with hydrogen chloride gas until the precipitation of the di-chloride was complete. The precipitate was separated by filtration.

80.8 parts by weight of S-aminobenzotriazole dihyrochloride were produced, the yield being 81.5% theoretical.

(B) To a stirred solution of 20.7 parts by weight of the S-aminobenzotriazole dihydrochloride, produced by the procedure described in Example 6A, dissolved in 100 parts by volume of pyridine, were slowly added 17.1 parts by weight of octanoyl chloride (caprylyl chloride) while keeping the temperature of the reaction mixture below 30 C. When the addition of the octanoyl chloride was completed, the resulting mixture was stirred for a further period of 2 hours and then poured into iced water.

The precipitated product was 5-octanoyl-amino-benzotriazole, which was filtered off and crystallised from methanol to yield 19.5 parts by weight of crystalline product, having melting point 198 C. The yield was 74.9% theoretical.

By repeating Example 6, but using in lieu of octanoyl chloride employed therein an equivalent amount of propionyl chloride there is obtained S-propionyl-aminobenzotriazole; and by using an equivalent amount of arachidic acid chloride, the corresponding final product, S-n-eicosyl-amino-benzotriazole is obtained.

EXAMPLE 7 The procedure described in Example 6 was carried out using 23 parts by weight of dodecanoyl chloride instead of the octanoyl chloride, the reactants and conditions being otherwise the same. The product was 18.7 parts by weight of crystalline 5-dodecanoylamino-benzotriazole having melting point 210 C. The yield was 59.1% theoretical.

EXAMPLE 8 The valuable properties of the compounds of the present invention are illustrated by the results of the following Pratt and Whitney type II oxidation-corrosion tests carried out at 425 F. in a synthetic ester based aero-gas turbine lubricant. The lubricant used was a 5-centistokes oil.

The tests were carried out for 48 hours using 5 litres Percent; VlS- Weight change of specimens Mg Al Alloy Alloy Sludge (mi lligrams) Test Benzotriazole additive cosity change 1 None 2 Benzotriazole 5 oemi-u;

OM G) S-methylbenzotriazole. 72 4 fi-ethylbenzotriazole. 2b 5 5-ndodecylbenzotri- 24 azole.

6 S-oetanoyl-arniuo benzotriazole.

7 5 dodecanoylamino 2 benzotriazole.

These results show that the 5-substituted benzotriazoles of the present invention are superior to benzotriazole and 5-methyl benzotriazole in preventing attack on copper and other metals, and in preserving the ester lubricant against degradation due to the presence of copper and other metals.

EXAMPLE 9 A specimen from the same bright acid-dipped copper foil was immersed in one of the following: 2% weight/ volume ethanol solution of benzotriazole; 2% weight/ volume ethanol solution of S-methylbenzotriazole; 0.2% weight/ volume ethanol solution of 5-octanoyl-aminobenzotriazole (as produced by the procedure described in Example 6); and 0.2% weight/volume ethanol solution of 5-dodecanoyl-aminobenzotriazole (as produced by the procedure described in Example 7). The four immersed specimens were maintained at C. for five minutes and they were then washed in distilled water and dried in hot air.

The resistance to tarnishing of the copper specimens was compared with that of a fifth specimen of the same acid-dipped, but otherwise untreated, copper foil as a control, by exposing the specimens to an atmosphere containing 10 parts per million by weight of hydrogen sulphide. The time taken for the onset of visible tarnish to occur was recorded as a measure of tarnish resistance.

The results are given in the following Table 4:

Table 4 Copper Specimen: Time (in minutes) Control 5 /2 Treated with benzotriazole 10 /2 Treated with S-methylbenzotriazole 10 /2 Treated with 5-octanoylaminobenzotriazole 13 Treated with S-dodecanoylaminobenzotriazole 19 These results demonstrate that the compounds of the invention effectively protect copper against tarnishing and that the protective properties are superior to that afforded by benzotriazole and S-methyl benzotriazole.

We claim:

1. composition for application to metal surfaces compnsmg:

(a) a corrosionor tarnish-inhibiting amount of a substituted benzotriazole of the formula wherein R is an alkanoylamino group containing from 3 to 20 carbon atoms and (b) a major amount of a solvent or carrier inert to the metal and to the substituted benzotriazole.

2. A composition as claimed in claim 1 wherein the solvent employed is Water, methanol, ethanol, a mineral oil or grease, ethylene glycol or polyethylene glycol or mixtures thereof.

3. A composition as claimed in claim 1 wherein the proportion of the substituted benzotriazole in the composition is within the range of from 0.001% to 5.0% by weight.

4. A composition as claimed in claim 3 wherein the proportion of the substituted benzotriazole in the composition is Within the range of from 0.01% to 1.0% by weight.

5. A functional composition resistant to deterioration of function through contact with a metal, Which composition comprises:

(a) a major amount of a functional material susceptible to such deterioration, which functional material is selected from the group consisting of polyethylene, polypropylene, natural and synthetic rubbers, mineral oils, anti-freeze compositions, and synthetic ester lubricants, and

(b) a substituted benzotriazole of the formula wherein R is an alkanoylarnino group containing from 3 to 20 carbon atoms, said substituted benzotriazole being present in an amount sufiicient to inhibit deterioration of function.

6. A functional composition as claimed in claim 5 wherein the functional material is polypropylene.

7. A functional composition as claimed in claim 5 wherein the functional material is a synthetic lubricant based on one or more carboxylic acid esters.

8. A functional composition as claimed in claim 5 wherein the proportion of the substituted benzotriazole in the composition is within the range of from 0.01% to 5% by weight.

9. A functional composition as claimed in claim 5 wherein the proportion of the substituted benzotriazole in the composition is within the range of from 0.05% to 2.0% by Weight.

10. A polymer composition resistant to degradation in the presence of copper, which composition comprises polypropylene and from about 0.01 to about 5% by weight, based on the total weight of polymer, of a substituted benzotriazole of the formula wherein R is alkanoylamino of from 3 to 20 carbon atoms.

References Cited UNITED STATES PATENTS 2,890,170 6/1959 Ragborg 252-50 XR 3,265,620 8/1966 Heiman 25250- XR FOREIGN PATENTS 793,115 4/1958 Great Britain. 986,068 3/1965 Great Britain.

PATRICK P. GARVIN, Primary Examiner. 

